Physics
drorzel | August 19, 2011As a follow up to Wednesday's sad balloon post, the repair that lofted it back to the ceiling was a temporary reprieve, unsurprisingly. After 24 hours, more or less, it had sunk back down to the point where the ribbon was just barely touching the floor.
On the one hand, it looks kind of pathetic again. On the other hand, though, this is a chance to do some more physics. See, I know how much ribbon I clipped off the end to get it to lift off again, and if it's fallen back to where it's just touching the floor, that means that the buoyant force due to the displaced air has decreased by an…
esiegel | August 18, 2011"The only relevant test of the validity of a hypothesis is comparison of prediction with experience." -Milton Friedman
Dark matter is one of the most important components of the Universe today. And yet in the public's eye, almost no one accepts it the way, say, the Big Bang is accepted. But it should be, and I'll show you why.
Image credit: NASA / ESA / Marc Davis.
I've talked before about what it took to convince me that dark matter was the best theory out there (and gave a simpler version here), but -- with alternative theories making big headlines -- it's important to truly know why dark…
drorzel | August 18, 2011I've moved on to the second of three academic writing projects I wanted to work on this summer (yes, I know I'm rapidly running out of summer...), which is a sort of review article on which I will be the only author. This creates an awkward situation in the introductory material, because it just feels wrong to use the first-person singular pronoun in an academic context. This is not a new problem for me-- my advisor pointed out that the only place I used "I" in my Ph.D. thesis was in the acknowledgements-- and other people have the same issue, so this seems like a perfect topic for a poll:…
drorzel | August 18, 2011I'm not much of a baseball fan, but we're edging our way toward football season, so I flipped to ESPN radio a couple of days ago, in time to hear Mike and Mike discussing Jim Thome's 600th home run. They were questioning how much meaning we should attach to home run records any more, given how many players were using steroids and other performance-enhancing drugs. In support of the record being a big deal, they played a clip of ESPN analyst Bobby Valentine pointing out that even with the steroid-inflated batting numbers, not that many guys are making a serious run at this particular milestone…
drorzel | August 17, 2011My birthday was two months ago, and SteelyKid's was the weekend before last, so we've had balloons running around the house for a good while now. Meaning that when I came into the library yesterday, I saw the sad little image on the right: a half-deflated Mylar balloon floating at about chest height.
Now, the first thought of a normal person on seeing this would be "Why didn't we throw this away a while ago?" My thought, since I've been on a bit of an everyday physics kick for a little while now, was "Hey, physics!"
"What do you mean?," you ask. "What physics is there in the sad balloon? It…
esiegel | August 16, 2011"Men occasionally stumble over the truth, but most of them pick themselves up and hurry off as if nothing had happened." -Winston Churchill
It's often said that you can't get something from nothing. And while this may be true for most practical applications of your life, it isn't true for our physical Universe.
And I don't just mean some tiny part of it; I mean all of it. When you take a look at the Universe out there, whether you're looking at the wonders of this world or all that we can see for billions of light years, it's hard not to wonder -- at some point -- where it all came from.…
drorzel | August 16, 2011Over at io9, they have a post on the finances of running a research lab at a major university. It's reasonably good as such things go, but very specific to the top level of research universities. As I am not at such an institution, I thought it might be worthwhile to post something about the finances of the sort of place I am at: a private small liberal arts college.
I'll follow the io9 article's format, but first, one important clarification:
Do you really do research at a small college? Yes, absolutely. At the upper level private liberal arts colleges, faculty are expected to be active…
esiegel | August 12, 2011"...it is reasonable to hope that in the not too distant future we shall be competent to understand so simple a thing as a star." -Arthur Eddington, 1926
(For Mike H., who wanted to know.)
The Sun -- like nearly all stars -- burns bright through its nuclear reactions, sending light, heat and energy out into the Universe over a timespan of billions of years.
Image credit: NASA / ISS / Space Shuttle Atlantis.
But it didn't need to be that way. With the mass of about 300,000 Earths, nearly all of it in the form of hydrogen fuel, you can just as easily imagine a huge nuclear explosion on the…
drorzel | August 12, 2011I am an inveterate driver of "back ways" to places. My preferred route to campus involves driving through a whole bunch of residential streets, rather than taking the "main" road leading from our neighborhood to campus. I do this because there are four traffic lights on the main-road route, and they're not well timed, so it's a rare day when I don't get stuck at one or more of them. My preferred route has a lot of stop signs, but very little traffic, so they're quick stops, and I spend more time in motion, which makes me feel like I'm getting there faster.
That's the psychological reason, but…
drorzel | August 12, 2011I'm sending a little pedagogical paper off to a journal today, and spent a while yesterday re-formatting it to meet their standards. This was particularly annoying for the references, as I had to go find a bunch of information that I don't usually write down. Which seems like a good topic for a poll:
A citation in a list of references should include:
Please note that the writing of papers is a classical phenomenon, and thus you may choose only one of these options.
My default answer, for the record, is the first choice. This is because my grad school training involved writing exclusively for…
drorzel | August 11, 2011I continue to be distracted from the paper-writing that I really ought to be doing by thinking about my classes this fall, and Joss Ives isn't helping. By being very helpful-- he posted a nice list of resources for active teaching. His blog has a bunch of other interesting stuff, too.
For the specific Matter and Interactions curriculum that we're using, it's probably also worth noting that they have a complete set of video lectures linked from their resources page. Unfortunately, these are complete with the "going over the syllabus" stuff in the early lectures, so the early going is a little…
esiegel | August 9, 2011"Magnetism, as you recall from physics class, is a powerful force that causes certain items to be attracted to refrigerators." -Dave Barry
One of the first "invisible forces" people encounter in this world is when they're first exposed to the humble magnet.
As the image above shows, you're most familiar with what magnets do to other magnetic (or magnetizable) materials, like the paper clip.
But magnets also exert forces on electrically charged objects. They do it, though, in a way that you're certainly not used to. Unlike gravity, where the gravitational field pulls you in the direction of…
drorzel | August 9, 2011An angle I had hoped to get to in last week's broader impacts post, but didn't have time for, was this piece questioning meet-the-scientist programs by Aimee Stern at Science 2.0:
Over the past several years, a growing number of trade associations, foundations and science and engineering companies have started major efforts to get scientists into schools and hopefully inspire students with what they do. The goal, of course, is to get kids interested in pursuing careers in scientific fields, by showing them just how cool science is.
But I wonder - no matter how well meaning, how much do these…
drorzel | August 9, 2011It's that time of year again, when I start thinking about my fall term classes. I would really prefer to put it off for another couple of weeks, and I will put off spending much time on class prep in favor of finishing up some paper-writing and other things, but when the calendar turns to August, I inevitably start thinking about what I'm going to be doing in September, no matter how much I'd like to be thinking about other things instead. This year is worse than most, because I'm planning to really shake things up with regard to the way I teach the intro mechanics course.
I've been doing…
drorzel | August 8, 2011When we got home from visiting Kate's family yesterday, there was a large shipping envelope from my agent waiting for us. This can mean only one thing: author copies of foreign editions!
That's the Czech edition, Jak nauÄit svého psa fyziku, which seems to have used the same glasses-wearing golden retriever as the Brazilian edition. The overlaid equations and graphics are lifted directly from the translated figures, which is nice.
My new favorite edition, though, is the Korean edition, whose cover designer went for "Puppy Innnn SPAAAAAACE!!!" as a concept:
There's nothing remotely…
esiegel | August 5, 2011"A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it." -Max Planck
(For Alan L., from the comments on this post.)
When you look out at the night sky, with the deepest, sharpest eyes possible, what is it that you see?
Image credit: NASA, ESA, R. Windhorst, S. Cohen, M. Mechtley, M. Rutkowski, R. O'Connell, P. McCarthy, N. Hathi, R. Ryan, H. Yan, and A. Koekemoer.
Galaxies! Lit by hundreds of billions of suns each (and that's just on average),…
drorzel | August 4, 2011I didn't pay that much attention to the mini-controversy over the NSF's proposed revision of its grant evaluation criteria when they were first released, because I was working on the book. I was asked to say something about it yesterday, though, and having gone to the trouble, I might as well say something on the blog, too.
The main source of complaint is the "Broader Impacts" section of the grant, a category that has always been sort of nebulous, but which the new standards attempt to clarify:
Collectively, NSF projects should help to advance a broad set of important national goals,…
sciencepunk | August 3, 2011YouTube user Henry Reich is behind an ongoing series of videos exploring concepts of physics in sixty second bursts. You might think that's too short a time to explain wave particle duality, and some of the videos did leave me hankering for extra information, but hey, that's more than I can say for any physics class I took at school!
(Thanks to Noah Raford for the title)
drorzel | August 3, 2011In the "ideas I wish I'd thought of first" file, the Canberra Times has an op-ed comparing politicians to quantum objects, because they seem to hold contradictory positions at the same time, and are impossible to pin down. It garbles the physics a little, and is very specific to Australia, though, so let's see if we can do a little better at identifying quantum properties of US politicians.
Duality: Quantum physics tells us that all objects in the universe have both particle-like and wave-like properties, and which you observer will depend on the design of your experiment. Similarly, quantum…
drorzel | August 2, 2011Over Twitter, somebody pointed to this article on astronomy outreach (free PDF from that link), which argues that everybody else should stop trying to be Brian Cox:
I've known Brian for years and worked with him before his celebrity status went supernova. I would love to say "I told you so" to all the TV commissioning editors who rejected my suggestions to use him as a presenter. I suspect Brian fnds it as ironic as I do that TV companies now regularly put out adverts looking for "the next Brian Cox".
As much as I love Brian's work, I don't think we need any more like him at the moment.…